It’s pretty easy for you to judge which career choice will generate the most value for yourself. At least in the short term, you can just compare the salaries that you would get in different roles (not that this will determine your happiness). Finance pays better than accounting, which in turn pays better than non-profit work. But have you considered the value your career will create for society as a whole?
The excellent 80,000 Hours website is filled with great ideas on how to think about this question. And even if you are a passionate believer in a particular philanthropic cause, the obvious answer of devoting your career to work in that cause is not necessarily the right one. As 80,000 hours points out, if you have a talent for finance or medicine, then the way to maximize the value that you create may be to earn a ton of money in your field of excellence and donate it to support organisations working for your chosen cause.
You also might want to consider the results of this study that tries to compare the value created and destroyed by different professions. They have to make a lot of assumptions to do this, but it is still interesting food for thought. The two most extreme professions that they looked at were tax accountants who “destroy £47 of value for every pound in value they generate”, and waste recycling workers who they estimate generate £12 in value for every £1 they receive in wages.